In the developing 3GPP Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS), it has been proposed that the user terminal use QPSK sequences for the generation of uplink reference signals. It was also decided that the user terminal would generate extended Zadoff-Chu (ZC) sequences for allocations of three (3) or more resource blocks to user terminals. For allocations of one (1) or two (2) resource blocks, 3GPP LTE user terminals will likely use “computer generated” sequences previously stored on the user terminal for the generation of uplink reference signals.
It is recognized generally that desirable sequence properties include a relatively low cubic metric (CM), good cross-correlation, and low complexity, which reduces memory requirements. Using QPSK sequences for the generation of reference signals provides an upper bound of 24 or 48 bits per sequence for 1 and 2 resource blocks, respectively, on the required memory. Using ZC sequences also reduces memory and provides improved CM and cross-correlation properties.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon a careful consideration of the following Detailed Description thereof with the accompanying drawings described below. The drawings may have been simplified for clarity and are not necessarily drawn to scale.